The present invention relates generally to an improved polyester for powder coating resin, and, more particularly, it relates to such a resin having improved coating and handling characteristics.
Various regulatory requirements have reduced the extent to which solvent based coatings can be used and have required the development of new kinds of coatings that do not affect the environment. However, the new resins for such coatings should have the characteristics of previously provided coatings so as to be impervious, smooth and glossy while having good resistance to weather conditions, abrasion and solvents. The resin should provide good flow characteristics, while having viscosity stability at high temperatures, have high reactivity with curing agents, and provide improved flexibility.
The prior art discloses a thermosetting resin in U.S. Pat. No. 4,124,570 having some of the desired properties. However, more viscosity stability would be desired than provided by the resin disclosed in the indicated patent; and increased flow characteristics, as well as improved flexibility are to be desired, beyond those provided by practicing the disclosure of this patent. At the same time, a thermosetting resin requiring reduced amounts of curing agent in the coating system is particularly desired.